The trends in vehicle design are towards lighter vehicles to improve fuel consumption. At the same time, manufacturers continue to demand more rigorous structural performance standards. The use of lighter hollow cross-sectional structural members that are used to form a vehicle body has lead to the need for additional reinforcement members in various locations in the vehicle body. As is well known, the vehicle body generally undergoes an electrocoat process in which the vehicle body is passed through a bath of anticorrosion fluid whereby an anticorrosion coating is deposited onto the vehicle body by electrolysis. The vehicle body is subsequently heated to bake the coating on the metal. Therefore, it is desirable that the reinforcement member does not prevent the provision of the anticorrosion coating on the inner surface of the hollow member by the electrocoat process.
It is known to provide longitudinal reinforcement members within the hollow structural members of the vehicle body. The reinforcement member is typically provided with an expandable adhesive on two surfaces, which can be foamed upon heating to bond the reinforcement member to two opposed walls of the structural member. However, this technique is not suitable for use in the electrocoat process described above as it can prevent the proper electrocoat over the entire inner surface of the structural member, which can lead to local areas of corrosion. Another known reinforcement member includes a light weight and high strength aluminum insert. However, it is difficult to isolate the aluminum insert from the structural member, which is typically formed of steel or steel alloy, and to correctly position the reinforcement member inside the structural member. It is also known to provide foamable plastic moldings within the structural members which can be foamed upon application of heat, such as is provided by the baking step in the electrocoat process, to provide a foamed baffle that fills the cross-section to provide sound adsorption. These moldings are generally used to provide acoustic baffles and seals.